What is the difference between sip and swallow?
They both seem to me pretty similar to one another.
1. Is it correct to say that 'to swallow' and 'to sip' carry the same idea but 'to swallow' is applicable both for food and drinks while 'to sip' is only for drinks ? It's what I can understand from dictionaries but I'm not sure.
2. Can I use 'to swallow' interchangeably with 'to sip' when I talk about drinks ?
3. The word 'sip' had been new to me before I encountered it for the 1st time in a story. Is it really common in everyday conversations or it's just from 'book language' ?

Question

What is the difference between sip and swallow?
They both seem to me pretty similar to one another.
1. Is it correct to say that 'to swallow' and 'to sip' carry the same idea but 'to swallow' is applicable both for food and drinks while 'to sip' is only for drinks ? It's what I can understand from dictionaries but I'm not sure.
2. Can I use 'to swallow' interchangeably with 'to sip' when I talk about drinks ?
3. The word 'sip' had been new to me before I encountered it for the 1st time in a story. Is it really common in everyday conversations or it's just from 'book language' ?

Answer

Swallowing is what you do after you have sipped, i would say, but some definitions include the swallowing. And yes, it only works with drinks.

When you sip, you take in small amounts of liquid in your mouth.

Answer

To take a sip is to drink a very small amount. It can only be used for drinks.
Swallow is the motion you usually do when you take medicine.

Medicine usually come in capsules so you usually need to "swallow" it then drink water.
You can use swallow with food as well.

When people eat, they usually "chew" before they "swallow".

Answer

The act of sipping refers to drinking in small quantities, so it is only about beverage and not food.

'To swallow' is to  cause (food or drink, for example) to pass through the mouth and throat into the stomach.